Tear strip for envelopes and other containers



Dec. 30, 1958 L. F. ZACKER TEAR STRIP FOR EINVELOPES AND OTHER CONTAINERS Filed Dec. 17, 1956 LAWRENGE F. ZAGKER INVENTOR.

United States Patent TEAR STRIP FOR ENVELOPES AND OTHER CONTAINERS Lawrence F. Zacker, San Diego, Calif.

Application December 17, 1956, Serial No. 628,872

3 Claims. (Cl. 229-51) This invention relates generally to. containers having means for making the same easily openable, and more particularly to a tear-strip construction for envelopes and other paper containers.

The primary object of this invention is to provide means for making a container easily opened by the breaking or parting of a paper panel constituting a portion of the container, the invention being particularly concerned with the provision of such an openable panel with optimum economy of manufacturing time and materials.

Another object of this invention, ancillary to the preceding object, is to provide a tear-strip consrtuction which is adapted to be incorporated in envelopes and other paper containers Without necessitating any radical changes in the accepted processes for manufacture of such containers.

Still another object of this invention is to provide a tearstrip construction which can be incorporated in envelopes and other containers by envelope and container manufacturing machines operating at high speeds. More specifically, it is an object of this invention to provide tearstrip structure for containers which enables the application of the plastic material in liquid form, and the weakening of the paper at the edges of this strip by the application of another liquid substance thereto.

Still another object of this invention is to provide novel means for weakening the paper at the edges of the tearstrip, this novel means consisting in the application of a substance which will cause rapid deterioration of the fiber content in the paper, the chemical deterioration being localized to very narrow lines and being controllable to a degree at least equivalent to the control of the weakening usually accomplished by mechanical means such as perforation and crimping or scoring, while being considerably more acceptable than the result of any such prior art perforation, crimping or scoring. Possibly the strongest reason for the general acceptability of this tearstrip construction is the fact that, although the paper is suitably weakened in localized portions extending along the edges of the tear-strip, the envelope or container still is in completely sealed condition until this seal is intentionally broken.

With these objects definitely in view, along with other objects which will appear hereinafter as this description proceeds, this invention resides in the novel construction, combination and arrangement of elements and portions as will be hereinafter described in detail in the specification, particularly pointed out in the appended claims, and illustrated in the accompanying drawings, in which:

Figure 1 is a plan view of a blank used for the construction of an envelope incorporating my invention;

Figure 2 is a rear elevational view of an envelope with the sealing flap in closed position, the envelope illustrating my invention as incorporated therein;

Figure 3 is a greatly enlarged fragmentary vertical sectional view, taken on the line 33 in Figure 1;

Figure 4 is an enlarged, fragmentary, vertical sectional view, taken on the line 4--4 in Figure 2;

Figure 5 is an isometric view of a cigarette package wherein my invention is incorporated.

Similar characters of reference designate similar or identical elements and portions throughout the specification and throughout the different views in the drawing.

Referring now to the drawing in detail, it should first be pointed out that this invention is not limited to use in envelopes, and that the term panel is used in this disclosure in its broadest sense. Such a panel will, however, ordinarily be constructed of paper, but the container may be of various types and forms, with the said panel ordinarily constituting an outside or superficial portion of the container. In the envelope illustrated, there is provided a substantially conventional envelope blank comprising a central panel 10, a pair of similar side flaps 12, a rear flap 14, and a sealing-flap 16. Only the sealing flaps 16 and one of the side fiaps 12 is shown as altered by this invention, although it will be understood that tear-strips can be incorporated with any or all of the flaps and may even be incorporated with more than one flap in a single envelope blank. Gummed interior surfaces 18 are provided on the rear flap 14.

The sealing flap 16 is provided with gummed interior surfaces 20 and is used in a substantially conventional manner. Portions 22 of the sealing fiap 16 are impregnated with a substance causing deterioration of the fiber content of the paper at a faster rate than the remaining parts of the corresponding paper panel which may be considered that portion of the sealing flap 16 adjacent to the central panel 10 of the envelope. As illustrated, the portions 22 are elongated and parallel and spaced apart to define therebetween a tear-strip 24. This tear-strip preferably extends beyond the adjacent edge portions of the paper panel concerned, in this case the sealing fiap 16, to constitute pull tabs 26. As illustrated in Figure 1, two pull tabs 26 are provided, one at each end of the sealing flap 16. The chemical substance used to make the paper deteriorate, as stated, is brushed, rolled or sprayed onto the panel, and the character of this substance will be further disclosed hereinafter. To improve the tensile strength of the tear-strip 24, I apply a thin layer 28 of tough material such as the plastics now used in the tearstrip art, although it is a feature of this invention that this layer 28 of tough material can be quite thin, when used in conjunction with the chemically weakened portions 22, and it is a feature of this invention that by virtue of this relative thinness the plastic can be applied in liquid form, preferably by spraying, but also conceivably by such processes as brushing or rolling the liquid plastic onto the tear-strip.

A tear-strip 30 may be provided in the side -flap 12 or in the rear flap 14 alternatively or additively to the provision of the tear-strip 24 in the sealing flap 16. In the drawing, only one such other positioning of the tear-strip is indicated, as at 30 in Figure 1, and it will be noted that elongated parallel portions 32, impregnated with a material causing deterioration of the fiber content of the paper extend along the sides of the tear-strip 30 and a pair of pull tabs 34 will be provided in this tear-strip, all according to the same principles of construction as already detailed above.

Examples of substances used to cause deterioration of the fiber contact in the paper are:

105% sodium hydroxide in water; Approximately 1% sodium hydroxide in alcohol; Approximately 1% sodium hydroxidein glycerine; 5-16% sodium hypochlorite (water);

220% chromic acid in Water;

15-10% nitric acid in water;

5-l0% nitric acid in alcohol.

All these substances are in liquid form and preferably Patented Dec. 30, 1958.

sprayed in parallel'lines to result in the weakened portions-22 and/or'32, although other means of application may be used. In machines having conventional apparatus for heat drying thegurnmed surfaces 18--20, a simple adaptation of the machines willpermit the heatdrying of the portion 22, and 32 wetted by the deteriorating chemical used. In this connection, it is noteworthy that where heatis employed, several other substances can be used, including S-l0% sulphuric acid in alcohol or water, it being understood thatwhere necessary the deteriorating chemical substance must be chosen with a view to avoiding discoloration of the paper, it being urged that the choice of the substance is a technological matter and something which those skilled in the art to which this invention appertains can easily accomplish in carrying out this invention.

Minor variation frornrthe form of the invention described herein may be resorted to without departure from the spirit and scope of this invention and the foregoing is represented'as illustrative rather than limiting. For example, the panel, while usually constructed of paper, may be of other materials used for wrappings and containers and in this event the substance causing localized deterioration will be chosen to suit the chemical composition of the material of the panel. When the invention is applied to a container such as the cigarette package indicated at 36, the panel concerned may be considered that portion of the wrapper, generally cellophane or the like, on the sides of the cigarette package. In this embodiment of the invention, elongated parallel portions 40 are impregnated with a chemical substance causing deterioration of the strength of the material therein, and these portions define an elongated tear-strip 42 which terminates in a pull tab 44 extending slightly beyond'theadjacent edge portions of the panel 38, the edge of the panel concerned being indicated at 46.

I claim:

1. In a container: a paper panel; elongated portions of said panel having therein a substance causing chemical deterioration of the fiber content of the paper in said portions at a rate greatly in excess of the rate of deterioration in the remainder of the panel; said portions constituting means to facilitate the opening of the container by parting the panel longitudinally of said portions; said portions being spaced apart and parallel and defining a tear strip in said panel;

2. In a container: a paper panel; elongated portions of said panel having therein a substance causing chemical deterioration of the fiber content of the paper in said portions at a rate greatly in excess of the rate of deterioration in the remainder of the panel; said portions constituting means to facilitate the opening of the con tainer by parting the panel longitudinally of said portions; said portions being spaced apart and parallel and defining a tear strip in said panel; and said tear strip being extended beyond adjacent edge portions of the panel to constitute a pull tab.

3. In a container: a paper panel; elongated portions of said panel having therein a substance causing chemical deterioration of the fiber content of the paper in said portions at a rate greatly in exces of the rate of deterioration in the remainder of the panel; said portions constituting means to facilitate the opening of the container by parting the panel longitudinally of said portions; said portions being spaced apart and parallel and defining a tear strip in said panel; and a thin layer of tough material secured on said tear strip.

References Cited in the file of this patent UNITED STATES PATENTS 2,097,505 Arp ct a1. Nov. 2, 1937 2,310,371 Lines et al. Feb. 9, 1943 2,315,116 Flizikowski Mar. 30, 1943 2,533,255 Will Dec. 12, 1950 2,801,745 Piester Aug. 6, 1957 

